KR100242224B1 - Resist composition and pattern forming method thereof and semiconductor manufacturing method - Google Patents

Abstract

An object of the present invention is to provide a resist composition capable of forming a resist pattern having excellent adhesion to a substrate while having transparency, sensitivity, resolution, and dry etching resistance that can be exposed in a short wavelength region.

To this end, the present invention provides a chemically amplifiable resist composition comprising a monomer unit I and (B) a cyclic carbonate moiety which is an insoluble polymer in its own basic aqueous solution and has a carboxylic acid or phenol protected with a specific protecting group. When the protective group of the monomer unit I containing the monomer unit II which has an ester group or an ether group, and is detach | desorbed by the action of an acid, it absorbs the base resin of polymer which can become soluble in basic aqueous solution, and imaging radiation, When decomposed, the photoacid generator may be combined to include an acid which may cause an acid which may cause desorption of the protecting group of the monomer unit I.

Description

A resist composition, the formation method of a resist pattern, and the manufacturing method of a semiconductor device

TECHNICAL FIELD This invention relates to a resist composition. More specifically, it is related with the resist composition which can use shorter wavelength ball | holes like an excimer resin as imaging radiation, and can develop with basic aqueous solution after exposure. The present invention further relates to a method of forming a positive resist pattern using such a resist composition and a method of manufacturing a semiconductor device using the resist pattern formed thereby as a mask.

In recent years, semiconductor integrated circuits have been highly integrated, and LSIs and VLSIs have been put into practical use, and the minimum line width of wiring patterns has reached the submicron range. For this reason, it is necessary to establish a microfabrication technique, and in the field of lithography, as a solution of the demand, the ultraviolet light of the exposure light source is shifted to the short wavelength of the atomic region, and the exposure method using the light source of the deep ultraviolet region wavelength is used. Research is also actively conducted. Accordingly, in the field of resist materials, there is a demand for the development of a material having both light absorption at the short wavelength as described above, good sensitivity and high dry etching resistance.

Under such a situation, photolithography using a fluoride crytone excimer laser (wavelength 248 nm, hereinafter referred to as KrF) as a new exposure light source in a semiconductor device manufacturing process is actively studied. In some cases, practical applications have begun. In addition, as a resist having a high sensitivity and a high resolution that can cope with such a short wavelength light source, a resist composition using a concept called a chemical amplification type has already been proposed in H. Ito et al. For example, JMJ Frechet et al., Proc.Microcircuit Eng., 260 (1982), H. Ito et al., Digest of Technical Papers of 1983 Symposium on VLSI Technology, 86 (1983), H. Ito et al., “Polymers in Electronics” , ACS Symposium Series 242, t. Davidson, ACS, 11 (1984), and US Pat. No. 4,491,628). The basic concept of such a resist composition can be readily understood in the literature, such as By raising the catalytic reaction at and improving the apparent quantum yield, the resist composition is increased in sensitivity and high resolution.

Chemical amplification type positive type which added photoacid generator (PAG) which has the effect of generating an acid by light to poly (t-butoxycarbonyloxystyrene) (t-BOCPVP) which has been studied extensively so far Taking a resist as an example, in the exposed portion of the resist, a t-BOC group as a protecting group is detached by heating after exposure, so-called "PEB (Post-Exposure Baking), to be isobutene and carbon dioxide. Therefore, the protonic acid generated at the time of desorption of t-BOC becomes a catalyst, the protecting group desorption reaction proceeds in series, and the polarity of the exposed portion is greatly changed. Therefore, a resist pattern can be formed by selecting the suitable developing solution which can respond to the big change of the exposure part polarity.

In recent years, in the manufacture of highly evolved semiconductor devices represented by one GDRAM, the use of an argon fluoride excimer laser (wavelength 193 nm, hereinafter referred to as ArF), which has a shorter wavelength than that of the KrF excimer laser, has been used as an exposure light source. It is expected. However, in such deep ultraviolet wavelength region, a resist based on polyvinylphenol (PVP), which has been available in KrF laser, also forms a pattern since the aromatic ring contained in the resist strongly absorbs light in this short wavelength region. Can't. Specifically, if a fine circuit pattern of 0.2 μm or less is formed by ArF lithography using a resist based on polyvinylphenol (PVP), for example, when the ArF laser is irradiated, the aromatic ring in the resist receives light. Due to the extreme absorption, the laser light does not reach the lower portion of the resist film, making it difficult to form a desired resist pattern.

In order to solve the problems as described above, the present inventors, a copolymer having a substituted hydrocarbon group in the structure, for example, adamantyl methacrylate-t-butyl methacrylate copolymer and adamantyl methacrylate A 3-oxocyclohexyl methacrylate copolymer or the like has been developed as a base resin of a chemically amplified resist, and has already been patented (see, for example, Japanese Patent Application Laid-Open No. 5-346668). The resist which has such a copolymer as a base resin has high transparency in the exposure wavelength, and is excellent also in dry etching tolerance, when an ArF laser etc. are used as an exposure light source. However, since the hydrophobicity is high, the adhesiveness to the substrate which is a base is poor, and there exists another problem which peels from a board | substrate at the time of alkali image development. Therefore, the present invention combines transparency, sensitivity, dry etching resistance, and resolution that can be exposed in a deep ultraviolet wavelength region such as an ArF laser, and it is urgent to develop a resist having good adhesion to a substrate.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, and combine transparency, sensitivity, etching resistance, and resolution that can be exposed in a deep ultraviolet wavelength such as an ArF laser. It is to provide a good resist composition.

It is also an object of the present invention to provide a resist composition which can use a basic aqueous solution as a developer and can form a fine pattern without swelling.

Another object of the present invention is to provide a method of forming a resist pattern using such a resist composition.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device using a resist pattern formed by the method of the present invention.

Other objects of the present invention will be readily understood from the following detailed description.

1 (a) to 1 (d) are cross-sectional views sequentially showing one preferred embodiment of a method of forming a resist pattern according to the present invention.

2 (a) to 2 (f) are cross-sectional views sequentially showing processes of a preferred embodiment of the method of manufacturing a semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

1 substrate (silicon substrate) 2 gate oxide film

3: polysilicon film 4: WSi film

5: resist film 6: N ^- diffusion layer

7: CVD oxide film 8: side wall

9: N ⁺ diffusion layer 10: thermal oxide film

11 interlayer insulation film 12 wiring

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, as a polymer used as a base resin in a chemically amplified resist composition, it is an ester group containing the monomeric unit which has a protected carboxylic acid or a phenol, and a cyclic carbonate part, or It has been found that it is effective to use at least a monomer unit having an ether group, and the present invention has been completed. Particularly, the cyclic carbonate portion contained in the polymer is partially ring-opened in the step of developing the resist film in the basic aqueous solution to be soluble in the developer, and further enhances good solubility in the developer due to the detachment of the protecting group from the carboxylic acid or phenol. There is. Moreover, since this cyclic carbonate part has high polarity, the favorable adhesiveness to a board | substrate can be ensured.

In one aspect, the present invention is a carboxylic acid or phenol which is a polymer insoluble in its basic aqueous solution and protected by a protecting group that can be detached from an acid selected from the group consisting of (A) an ester group, an ether group, an acetal group and a ketal group. A monomer unit II having an ester group or an ether group comprising a monomeric unit I having a cyclic carbonate portion and (B) at least in its structure, and wherein the protecting group of the monomeric unit I is desorbed by the action of an acid, A combination of a base resin made of a polymer which can be made soluble in a linear aqueous solution, and a photoacid generator capable of absorbing and decomposing imaging radiation and generating an acid which may cause desorption of the protecting group of the monomer unit I. A resist composition developable in a basic aqueous solution is characterized by the above-mentioned.

In another aspect, the present invention provides a method of forming a resist pattern, comprising the following steps: The resist composition of the present invention is applied onto a substrate, and the formed resist film is a photo acid generator of the resist composition. A method of forming a positive resist pattern, comprising selectively exposing an imaging radiation capable of inducing decomposition of the film, and developing the resist film after exposure in a basic aqueous solution.

In the method for forming a resist pattern according to the present invention, the resist film formed on the substrate to be treated is preferably subjected to heat treatment before and after the selective exposure step. That is, in the method of the present invention, the resist film is subjected to a prebaking treatment before the exposure, and before the development is performed after the exposure, a post-baking treatment as described by PEB (Post-Exposure Baking) is first performed. These heat treatments can be advantageously performed in accordance with a conventional method.

In another aspect, the present invention provides the following steps: The resist composition of the present invention is applied onto a substrate to be formed to form a resist film, and the resist film is subjected to decomposition of the photoacid generator of the resist composition. Selectively exposing with an image forming radiation, developing the resist film after exposure in a basic aqueous solution to form a resist pattern, and using the resist pattern as a mask to remove the substrate under treatment by etching; The manufacturing method of the semiconductor device characterized by the above-mentioned is provided.

In the method for manufacturing a semiconductor device according to the present invention, if necessary, the formed resist pattern may not be used as a mask for etching the underlying material, but may be used as it is as one element of the semiconductor device, for example, an insulating film.

In the method for forming a resist pattern and the method for manufacturing a semiconductor device according to the present invention, the step of exposing the resist film with imaging radiation can be performed using various exposure light sources depending on the characteristics of the resist to be used and the like. Preferably, a light source in a short wavelength region, such as a KrF excimer laser or an ArF excimer laser, can be used to maximize the properties of the resist.

The resist composition, the method of forming a resist pattern, and the method of manufacturing a semiconductor device according to the present invention can be implemented in various forms, as can be easily understood in the following detailed description, respectively.

TECHNICAL FIELD This invention relates to forming a positive resist pattern on a to-be-processed substrate, and relates to the chemically amplified resist composition which can be developed by basic aqueous solution. This resist composition of this invention combines the base resin of the film-forming polymer which is insoluble in the basic aqueous solution, and the photoacid generator which can generate | occur | produce an acid as a result of exposure of the imaging radiation. Here, the film-forming polymer used as the base resin has (A) a carboxylic acid or phenol protected with a protecting group that can be detached from an acid selected from the group consisting of an ester group, an ether group, an acetal group and a ketal group as described above. Monomer unit II having an ester group or ether group comprising monomeric unit I and (B) cyclic carbonate moiety is included at least in its structure, and when the protecting group of monomeric unit I is released by the action of an acid, Polymers that can be soluble.

These film-forming polymers are usually copolymers (bicomponent copolymers) of the monomer units I and II described above or multicomponent copolymers in which third and fourth monomer units are combined with these monomer units (for example, , Three-component copolymer). The monomer unit used to construct these copolymers may be a vinylphenol monomer unit, an N-substituted maleide monomer unit, or a styrene monomer unit, in consideration of obtaining dry etching resistance of about novolak resist. And (meth) acrylate monomer units having an ester group including a plurality of or polycyclic alicyclic hydrocarbon moieties, that is, acrylate and methacrylate monomer units. Particularly suitable monomer units include, for example, (meth) acrylate based monomer units in monomeric units I with protected carboxylic acids, vinylphenol based monomeric units in monomeric units I with protected phenols, and cyclic carbonate moieties. In monomeric unit II which has an ester group or an ether group, it is a (meth) acrylate type monomer unit. In particular, the (meth) acrylate-based monomer unit is important in that light absorption at such wavelength is small when using a short wavelength region as an exposure light source. In addition, in connection with this point, it is preferable to use the monomer unit which does not contain the aromatic ring which absorbs the light of a short wavelength region largely, and a chromophore with a large molar extinction coefficient, such as a conjugated double bond.

In addition, if the ester group, ether group, acetal group and ketal group which are the protecting group of the monomeric unit I which has the said carboxylic acid or phenol are each introduce | transduced in the literature etc., there is no restriction | limiting in particular. Examples of suitable protecting groups include, but are not limited to, those listed below.

In said formula, R is an alkyl group which has 1-4 carbon atoms, for example, a methyl group, an ethyl group, etc., m is an integer of 4-8, n is an integer of 1-3.

In addition, in the case of the monomer unit I which has a phenol, it can introduce advantageously as an airway protecting group as follows.

Moreover, especially when an ArF emigmer laser is used as an exposure light source, an alicyclic hydrocarbon group is suitable as a protecting group of carboxylic acid ester. Particularly suitable alicyclic hydrocarbon groups are alicyclic or polycyclic alicyclic hydrocarbon groups which have a tertiary alcohol skeleton and are ester-bonded to the tertiary alcohol. These alicyclic hydrocarbon groups are particularly useful in terms of transparency and dry etching resistance. Suitable polycyclic branched hydrocarbon groups are norbornane, adamantane, bicyclo (2,2,2) octane and the like, some of which are illustrated below.

The film-forming polymer which can be advantageously used in the practice of the present invention is not particularly limited to those listed below, but is represented by the following structural formulas (I), (II) and (III). Polymers. In addition, o, p, and q in a formula are the number of the monomeric unit (repeated unit) required in order to obtain said weight average molecular weight, respectively.

In the above formula, X is any substituent, for example, a hydrogen atom, a halogen atom, for example chlorine, bromine, etc., except when there is a clue, a lower alkyl group, for example, a methyl group And -CO ₂ -R (wherein R is an organic group), a cyano group, and the like, PRO is a protecting group as in the typical example shown above, x is an integer of 1 to 10, and y is an integer of 1 to 3. .

In the above formula, X is PRO, x and y are the same as the above definition, respectively.

In the above formula, ALC is an alicyclic hydrocarbon group, and PRO is as defined above. Here, the suitable example of alicyclic hydrocarbon group ALC is not limited to what is described below, but contains the following groups.

In said formula, x and y are the same as the said definition, respectively, z is an integer of 2-6.

The molecular weight (weight average molecular weight, Mw) of the (meth) acrylate type polymer and other film forming polymer which are obtained by superposition | polymerization of the above-mentioned monomeric unit, and can be advantageously used in the practice of this invention, is wide Although it is changeable in the range, Preferably it is the range of 2000-1 million, More preferably, it is the range of 5000-50000.

In addition, these (meth) acrylate type polymers and other film-forming polymers can be manufactured using the polymerization method generally used in polymer chemistry, respectively. For example, although the (meth) acrylate type polymer of this invention abbreviate | omits detailed description in this specification, the predetermined monomer component of 2,2'- azobisisobutyronitrile (AIBN) as a free radical initiator is used. It can be produced advantageously by free radical polymerization in the presence.

Monomer unit II having an ester group or ether group comprising a cyclic carbonate moiety and a film-forming polymer comprising the same can also be produced using a general polymerization method. For example, (1) W. N. Haworth et al., J. Chem. Soc., 151 (1930), (2) K. Katsuta et al., Bull. Chem. Soc. Jpn., 58, 1699 (1985) and (3) R. L. Let singer et al., J. Org. As disclosed in Chem., 32, 296 (1967), monomers having 1,2- or 1,3-diol moieties can be used in the presence of a basic compound in the presence of a basic compound, phosgene (1), trichloroacetyl chloride (2). Or a reagent such as chloro-p-nitrophenoxycarbonate (3). Further, as disclosed in German Patent No. 3529263 (1987) to G. brindoepke, the monomer having an epoxy group can be easily synthesized by introducing carbon dioxide at atmospheric pressure in the presence of a catalyst such as lithium chloride. In the latter method, a polymer reaction is also possible. For example, a monomer having an epoxy group represented by glycidyl methacrylate is copolymerized with a desired partner in advance, and the epoxy group of the copolymer can be easily prepared by the above method. And to cyclic carbonates (see, eg, K. Kihara et al., Macromol. Chem., 193, 1481 (1992) and the like).

As can be understood from the above description, the present invention provides (A) a monomer unit I having a carboxylic acid or phenol protected with an ester group, an ether group, an acetal group or a ketal group which can be deprotected by an acid catalyst, and (B A novel resist comprising as a base resin a polymer comprising at least the monomer unit II having an ester group or an ether group comprising a cyclic carbonate moiety in its structure. Here, when dry etching resistance (for example, RIE resistance) about the novolak resist currently used is needed, the content rate of the alicyclic type compound in which the phenolic monomeric unit in the polymer is ester group or ether group is 50 mol%. I need to do that. In addition, among the cycloaliphatic compounds, higher dry etching resistance can be obtained by using a polycyclic alicyclic ring to which a ring is highly bonded, as an ester group or an ether group. In addition, transparency in the wavelength (193 nm) of an ArF excimer laser is very advantageous because the above-mentioned alicyclic or polycyclic alicyclic system does not contain a conjugated double bond or an aromatic ring with strong absorption.

By the way, the content rate of the monomer unit I which has a carboxylic acid or phenol which can be deprotected by an acid catalyst in the polymer of this invention becomes like this. Preferably it is 20 to 80 weight%. If the content of this monomer unit is less than 20% by weight, a satisfactory phenomenon cannot be obtained and patterning becomes impossible accordingly. If the content of the monomer unit is higher than 80% by weight, on the contrary, it is changed so that it can be dissolved in a basic aqueous solution. The content rate of such a monomer unit becomes like this. More preferably, it is 30 to 70 weight%.

The polymer as the base resin of the present invention is, in addition to the monomer unit I and the monomer unit II described above, as long as the properties of the resist are not impaired, the third and fourth monomer units such as 2-hydroxyethyl methacrylate and methyl. You may have monomers, such as methacrylate. That is, as mentioned above, the polymer of the present invention may be a three-component copolymer or a four-component copolymer in addition to the two-component copolymer. When using an ArF excimer laser as an exposure light source, it is preferable to use the (meth) acrylate type polymer which is well known to have high transparency in the deep ultraviolet region instead of a phenol or a monomer unit having a conjugated double bond. Also. In the case of using such a (meth) acrylate crab polymer, in order to improve dry etching resistance, it is preferable to include an alicyclic or polycyclic alicyclic compound in an amount of 20% or more and less than 100% in the ester group of the polymer. Preferably, it is 30 to 70% more preferably.

The photoacid generator (PAG) used in combination with the film-forming polymer as described above in the resist composition of the present invention is a photoacid generator generally used in the chemistry of the resist, namely ultraviolet rays, far ultraviolet rays, It may be a material generating protonic acid by irradiation of radiation such as vacuum ultraviolet rays, electron beams, X-rays, laser light. Suitable photoacid generators in the practice of the present invention include, but are not limited to, those listed below.

(1) Onium salts represented by the following formula:

(In the above formula, R ₁ represents a t-butyl group, an alkyl group, for example, a methyl group, halogen, for example, chlorine, cancellation, etc., an aryl group, for example, a phenyl group, etc., and X ₁ Represents BF ₄ , BF ₆ , PF ₆ , AsF ₆ , SbF ₆ , CF ₃ SO ₃ , ClO _4, etc.)

(2) sulfonic acid esters represented by the following formula:

(3) halides represented by the following formula:

(In the above formula, X ₂ is halogen, for example, Cl, Br or I, provided that one of the -CX ₂ groups may be a substituted or unsubstituted aryl group or alkenyl group).

(4) an s-triazine derivative represented by the following formula:

(In the above formula, X ₂ is the same as the above definition.)

(5) disulfone derivatives represented by the following formula:

Ar-SO ₂ -SO ₂ -Ar

(In the above formula, Ar represents a substituted or unsubstituted aromatic group, for example, a phenol group or an alicyclic group substituted with a phenol group or a halogen, methyl group, t-butyl group or the like).

(6) an imide compound represented by the following formula:

(In the above formula, X ₁ is the same as the above definition).

These photoacid generators can be used in various amounts in the resist composition of this invention. According to the knowledge of the present inventors, the usage-amount of a photo acid generator becomes like this. Preferably it is 0.1-50 weight% based on the whole quantity of the film formation polymer as base resin. If the amount of this photoacid generator exceeds 50% by weight, light is excessively absorbed, and as a result, patterning cannot be performed. The amount of the photoacid generator used is more preferably 1 to 15% by weight based on the total amount of the polymer.

In addition, in connection with the above, the transmittance | permeability (the value at the time of forming a resist film with a film thickness of 1 micrometer on a quartz substrate) in the exposure wavelength of the resist composition of this invention which consists of a film forming polymer and a photo acid generator is 20%. As mentioned above, it is preferable to consider the structure of a polymer and a photo acid generator, and the usage-amount of a photo acid generator.

In the resist composition of the present invention, the above-mentioned film-forming polymer and photoacid generator are usually dissolved in a suitable organic solvent, and can be advantageously used in the form of a resist solution.

Useful organic solvents for preparing a resist solution are recommended, such as ethyl lactate, methyl amyl ketone, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate, and the like. It is not limited. Although these solvent may be used independently, you may mix and use two or more types of solvent as needed. Although the usage-amount of these solvents is not specifically limited, It is preferable to use in the amount sufficient to acquire the viscosity suitable for application | coating methods, such as spin coating which is a typical application | coating method, and desired resist film thickness.

In the resist solution of this invention, you may use an auxiliary solvent in addition to the above-mentioned solvent (especially a main solvent) as needed. Although the use of an auxiliary solvent is not necessary depending on the solubility of the solute, when a solubility with a low solubility is used, it is usually preferable to add it in an amount of 1 to 20% by weight relative to the main solvent, more preferably 10 to 20 Weight percent. Examples of useful co-solvents include, but are not limited to, those listed below, butyrate acetate, γ-butyrolactone, propylene glycol methyl ether and the like.

The resist composition according to the present invention will be fully understood from the above description. Here, the resist composition of the present invention is further described in terms of function, as follows:

In the polymer used as a base resin, the biggest characteristic of this invention WHEREIN: The protecting group of the carboxylic acid or phenol which detach | desorbs from the conventional acid does not only detach | desorb by heating after exposure, but also ring-opens in the developing solution which cyclic carbonate becomes basic aqueous solution, This makes it possible to simultaneously realize higher sensitivity and resolution than conventional chemically amplified resists (only one monomer component in the copolymer is removed to change the solubility). In addition, regarding the conventional chemically amplified resist, for example, Kaimoto et al., Proc. SPIE, vol. 1672, 66-73 (1992).

When using an ArF excimer laser as an exposure light source, it is preferable to use the (meth) acrylate type polymer which does not contain a conjugated double bond as a base resin. Since the alicyclic, polycyclic alicyclic and cyclic carbonates each do not contain a chromophore having a large molar extinction coefficient at a wavelength of 190 to 250 nm, the acid is generated by absorbing and decomposing an appropriate amount of imaging radiation. When combined with a photo acid generator (PAG) that can be detached, a highly sensitive resist that can advantageously cope with exposure using deep ultraviolet light having a wavelength of 193 nm can be realized.

PAG absorbs the imaging radiation and generates an acid. The generated acid becomes a catalyst and is heated to generate the following reaction in the exposed portion of the resist film. In addition, although the cyclic carbonate in a polymer is generally stable with respect to an acid, since PAG used in combination with this polymer produces | generates a super strong acid and heat | fever is added, a part decarboxylates and changes into a diol.

In the exposure part which became high polarity, since the ester group detach | desorbed, the following reaction arises immediately between image development by basic aqueous solution, and developability by basic aqueous solution improves further. In the unexposed portion of the resist film, since the relative monomer unit is unreacted, the hydrophobicity is strong and the developer does not penetrate. Therefore, the following reaction is limited only to the very surface of the resist film. For this reason, there is no adverse effect like dissolution of an unexposed part and a contrast falling.

In the polymer of the present invention, since a functional group which can be easily detached by heating in the presence of an acid catalyst is introduced into the carboxylic acid or phenol portion of the monomer unit, protonic acid can be regenerated by the desorption, thus providing high sensitivity. Can be achieved. In addition, since the carboxylic acid or phenol is produced after the detachment of the functional group, the exposed portion of the resist film becomes soluble in the base, and thus can be developed in the basic aqueous solution.

Since the obtained resist pattern dissolves and removes an exposure part, it is a positive pattern. Moreover, in this invention, since pattern formation is performed using the change of the polarity produced | generated in a polymer, the pattern without swelling is obtained.

The present invention also provides a method of forming a resist pattern, in particular a positive resist pattern, on a substrate to be treated using the resist composition as described above. The method of forming a resist pattern according to the present invention comprises the following steps:

The resist composition of the present invention is applied onto a substrate to be treated, and the formed resist film is selectively exposed to the imaging radiation in which the resist composition can induce decomposition of the photo acid generator, and the exposed resist film is developed in a basic aqueous solution. It characterized in that, including.

Formation of the resist pattern by the method of this invention can be normally performed as follows (refer FIG. 1).

First, after preparing the to-be-processed board | substrate 1 as shown to FIG. 1 (a), on the to-be-processed board | substrate 1, as shown to FIG. 1 (b), the resist composition of this invention is apply | coated The resist film 5 is formed. The substrate to be processed may be a substrate commonly used in semiconductor devices and other devices, and examples thereof include an insulating crystal substrate such as a silicon substrate, a glass substrate, a nonmagnetic ceramic substrate, a compound semiconductor substrate, and alumina. Can be enumerated. In addition, an additional layer, for example, a silicon oxide film, a metal layer for wiring, an interlayer insulating film, a magnetic film, or the like may exist above these substrates, and various wirings, circuits, and the like may be formed. In this specification, these additional layers or various wirings, circuits, and the like are collectively referred to as "etched layers". If the etched layer specifically lists typical examples of the material, metal silicides such as PSG, TEOS, SiON, TiN, amorphous carbon, Al-Si, Al-Si-Cu, WSi, polysilicon and amorphous silicon , SiO ₂ , Ga-As, and the like. In addition, the substrate to be processed may be hydrophobized in accordance with a conventional method in order to improve the adhesion of the resist film to the substrate. As a suitable hydrophobization treatment agent, 1,1,1,3,3,3-hexamethyldisilazane etc. are mentioned, for example.

As mentioned above, it is preferable to apply | coat a resist composition on a to-be-processed board | substrate using it as a resist solution. Application of the resist solution is a technique of use of spin coating, roll coating, dip coating, etc., but spin coating is particularly useful. Although the range of about 0.1-200 micrometers is recommended for the resist film thickness, about 0.1-1.5 micrometers is recommended in the case of KrF exposure. In addition, the thickness of the formed resist film can be changed widely according to factors, such as the use of the resist film.

The resist film coated on the substrate is preferably prebaked for about 60 to 120 seconds at a temperature of about 60 to 160 ° C. before selectively exposing it to imaging radiation. This prebaking can be performed using heating means commonly used in a resist process. As suitable heating means, a hotplate, an infrared heating oven, a microwave oven, etc. are mentioned, for example.

Next, as shown in FIG. 1 (c), the resist film 1 after prebaking is selectively exposed to imaging radiation by a commercial exposure apparatus. In the figure, exposure radiation is indicated by an arrow. Suitable exposure apparatuses are commercial ultraviolet (ultraviolet, deep ultraviolet) exposure apparatus, X-ray exposure apparatus, electron beam exposure apparatus, excimer stepper, and the like. As the exposure conditions, appropriate conditions can be selected each time. In particular, in the present invention, as mentioned above, an excimer laser (A KrF laser having a wavelength of 248 nm and an ArF laser having a wavelength of 193 nm) can be advantageously used as an exposure light source. In addition, in the present specification, when the term "radiation" is used, it means light from various light sources, that is, ultraviolet light, far ultraviolet light, deep ultraviolet light, electron beam (EB), X-ray, laser light and the like. I shall do it. As a result of this selective exposure, the dissolution inhibiting compound contained in the exposure region of the resist film absorbs and decomposes the radiation, so that the exposure is solubilized with respect to the basic aqueous solution.

Next, post-exposure baking (PEB) of the exposed resist film causes desorption reaction of the protecting group using the acid as a catalyst. This post-exposure baking can be performed similarly to the above prebaking. For example, the baking temperature is about 60-150 ° C., preferably about 100-150 ° C.

After the post-exposure baking is completed, the resist film after exposure is developed in a basic aqueous solution as a developer. For this phenomenon, a commercial developing device such as a spin developer, a deep developer, or a spray developer can be used. Here, the basic aqueous solution which can be advantageously used as a developer is an aqueous solution of a hydroxide of a metal belonging to Groups I and II of the periodic table represented by potassium hydroxide or the like or an organic base containing no metal ions such as teraalkylammonium hydroxide. Aqueous solution. The basic aqueous solution is more preferably an aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH) or the like. Moreover, such basic aqueous solution may contain additives, such as surfactant, etc. in order to improve the image development effect. As a result of the development, as shown in FIG. 1 (d), the exposed area of the resist film is dissolved and removed, and only the unexposed area remains on the substrate 1 as the resist pattern 5.

This invention also provides the method of manufacturing a semiconductor device using the resist pattern formed as mentioned above as a mask. The manufacturing method of this semiconductor device by this invention is the following process:

The resist composition of the present invention is applied onto a substrate to be treated to form a resist film, the resist film is selectively exposed to imaging radiation capable of inducing decomposition of the photoacid generator of the resist composition, and the resist film after exposure is basic. It develops in aqueous solution, and forms a resist pattern, The said to-be-processed board | substrate of the base material is removed by etching using the said resist pattern as a mask, It is characterized by the above-mentioned.

In this method, the formation of the resist film, the selective exposure by radiation, and the formation of the resist pattern can be advantageously performed in accordance with the method described above with reference to FIG.

In addition, the following etching process can be performed by wet etching or dry etching, Preferably it is dry etching. As is well known, dry etching etches a substrate to be processed in a gaseous phase. Suitable dry etching is plasma etching, for example reactive ion etching (RIE), reactive ion beam etching (RIBE), ion beam etching and the like. These dry etching can be performed on predetermined conditions using the commercially available etching apparatus.

In addition, although the resist pattern formed by the method of this invention is normally advantageously used as a mask of the etching of the to-be-processed substrate which exists as a base, as long as the resist pattern satisfy | fills predetermined requirements regarding a characteristic etc. of a semiconductor device, It may be used as one element, for example, as an insulating film.

Here, the "semiconductor device" is not particularly limited, and refers to a general semiconductor main circuit such as IC, LSI, VLSI, or other related devices as generally recognized in the technical field. More specifically, the semiconductor device of the present invention is a semiconductor device having a pattern rule of 0.2 μm or less, that is, capable of high integration or fine processing. As such a semiconductor device, it is not limited to what is enumerated below, For example, a MOS transistor etc. are mentioned.

The manufacture of a semiconductor device by the method of the present invention can be carried out as shown in the order of FIG. In addition, the example of illustration is a manufacture example of a MOS transistor.

First, as shown in FIG. 2 (a), the gate oxide film 2, the polysilicon film 3, and the SWi film 4 are sequentially formed on the silicon substrate 1. Formation of each thin film can be performed by thermal oxidation, chemical vapor deposition (CVD method), etc. as is normally done in this technical field.

Next, the resist composition according to the present invention is applied onto the WSi film, which is the uppermost layer, to form a resist film. The resist film is selectively irradiated with radiation suitable for its patterning, for example excimer laser light, and developed in a basic aqueous solution. The underlying polysilicon film and the WSi film are dry-etched using the obtained resist pattern as a mask. After forming a gate electrode made of a polysilicon film and a WSi film, phosphorus is implanted by ion implantation to form an N ⁻ diffusion layer having an LDD structure. Through such a series of steps, a gate electrode structure as shown in FIG. 2 (b) is obtained. In the figure, reference numeral 5 denotes a resist film (used as a mask), and reference numeral 6 denotes an N-diffusion layer.

After the resist film on the gate electrode is peeled off, the oxide film 7 is entirely formed by CVD, as shown in FIG. 2 (c). In addition, the formed CVD film 7 is anisotropically etched as shown in FIG. 2 (d) to form sidewalls 8 in the sidewall portions of the gate electrodes made of the polysilicon film 3 and the WSi film 4. do. Subsequently, ion implantation is performed using the WSi film 4 and the sidewalls 8 as a mask to form an N ⁺ diffusion layer 9. Next, as shown in FIG. 2 (e), the gate electrode is covered with the thermal oxide film 10.

Finally, an interlayer insulating film is formed over the top layer of the substrate by CVD, and the resist composition of the present invention is applied again and selectively etched to form a hole pattern in the wiring forming portion. Further, using the resist pattern as a mask, the underlying interlayer insulating film is etched to open a contact hole. When the aluminum (Al) wiring is filled in this contact hole, as shown in FIG. 2 (f), the N-channel fine MOS transistor is completed. In the figure, reference numeral 11 denotes an interlayer insulating film, and reference numeral 12 denotes an Al wiring.

Next, the present invention will be described with reference to several examples regarding the synthesis of a film-forming polymer as a base resin, preparation of a resist composition, formation of a resist pattern, and production of a semiconductor device. In addition, the following Example is only an example, The scope of the present invention is not limited by this.

Example 1

Synthesis of 4-t-butoxycarbonyloxystyrene / 4-vinylphenol / propylenecarbonate methacrylate copolymer

In a 100 ml eggplant flask, 7.82 g (63 mmol) of vinylphenol, 4.69 g (33 mmol) glycidyl methacrylate, Teflon ^™ -coated stiring bar, 33 ml dioxane and 2.44 g (14.9 mmol) of azobisisobutyronitrile (AIBN) was added and stirred at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise with 1.5 liter of ether containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Teflon ^™ coated sterling bar, a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of N-methylpyrrolidone (NMP). The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by evaporating dry ice. The reaction mixture was added dropwise to 1.5 liter of water-ethanol mixed solution (1: 1). The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. 10.2 g of a white resin powder were obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that phenol: methacrylate = 70: 30.

The white powder obtained was then placed in a 100 ml eggplant flask and Teflon ^™ coated stir bars and 100 ml dioxane were added. In a nitrogen atmosphere, 1.68 g (15 mmol) of potassium-t-butyldicarbonate was added and stirred at 0 ° C for 4 hours, followed by 3 g (13.9 mmol) of di-t-butyldicarbonate, followed by 3 at 0 ° C. It stirred for hours. The reaction solution was concentrated and then dropwise added to 1.5 liters of methanol to precipitate. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was phenol: butoxycarbonirenpanol: methacrylate = 31: 39: 30. The transmittance | permeability in wavelength 248nm of this copolymer is 60% (film thickness of 1 micrometer, on a quartz substrate), and shows that it is excellent in transparency. In addition, other analysis results are as follows.

Quantity: 8 g (63.9%).

Weight average molecular weight: 17800 (standard polystyrene conversion).

Dispersion: 1.78

IR (KRS-5, cm- ¹ ): 3500, 1815, 1160, 1103.

Example 2

Synthesis of methacrylic acid tetrahydropyranyl / methacrylate propylene carbonate copolymer

In a 100 ml eggplant flask, 5 g (29.4 mmol) methacrylate tetrahydropyranyl, 4.17 g (29.4 mmol) glycidyl methacrylate, Teflon ^™ -coated sterling bar, 19.6 ml dioxane and 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) was added and stirred at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the sedimentation-drying operation was repeated twice in the same manner as fresh. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Teflon ^™ coated sterling bar, a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of N-methylpyrrolidone (NMP). The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was tetrahydropyranyl: carbonate = 49: 51. The transmittance | permeability in wavelength 248nm and 193nm of this copolymer is 96% and 64% (film thickness of 1 micrometer, on a quartz substrate), respectively, and shows that transparency is excellent. In addition, other analysis results are as follows.

Quantity: 7.03 g (76.7%)

Weight average molecular weight: 13900 (standard polystyrene equivalent)

Dispersion: 1.75

IR (KRS-5, cm- ¹ ): 1812, 1724, 1259, 1161, 1103.

Example 3

Synthesis of Methacrylic Acid 2-Methyl-2-adamantyl / Methacrylic Acid Propylenecarbonate Copolymer

In a 100 ml eggplant flask, 7.15 g (29.4 mmol) methacrylic acid 2-methyl-2-adamantyl, 4.17 g (29.4 mmol) glycidyl methacrylate, Teflon ^™ -coated sterling bar, 19.6 ml of dioxane and 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) were added and the mixture was stirred at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Teflon ^™ coated sterling bar, and a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of NMP. The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was adamantyl: carbonate = 52: 48. The transmittances of the copolymer at wavelengths of 248 nm and 193 nm are 96% and 63% (film thickness of 1 m, on a quartz substrate), respectively, indicating that the transparency is excellent. In addition, other analysis results are as follows.

Quantity: 7.92g (70%)

Weight average molecular weight: 18500 (standard polystyrene equivalent)

Dispersion: 1.75

IR (KRS-S, cm- ¹ ): 1814, 1731, 1259, 1157, 1101.

Example 4

Synthesis of Methacrylic Acid 3-Oxocyclohexyl / Methacrylic Acid Propylene Carbonate Copolymer

In a 100 ml eggplant flask, 5.35 g (29.4 mmol) methacrylic acid 3-oxocyclohexyl, 4.17 g (29.4 mmol) glycidyl methacrylate, Telfon ^TM -coated sterling bar, 19.6 ml dioxane And 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) were added, followed by stirring at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Telfon ^™ coated sterling bar, and a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of NMP. The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H-NMR, and it was found that the copolymerization ratio was oxocyclohexyl: carbonate = 49:51. The transmittance | permeability in wavelength 248nm and 193nm of this copolymer is 96% and 65% (film thickness of 1 micrometer, on a quartz substrate), respectively, and shows that transparency is excellent. In addition, other analysis results are as follows.

Quantity: 6.80 g (66%)

Weight average molecular weight: 14200 (standard polystyrene equivalent)

Dispersion: 1.68

IR (KRS-R, cm- ¹ ): 1814,1730, 1262, 1160, 1103.

Example 5

Synthesis of Methacrylic Acid Mealonic Lactone / Methacrylic Acid Propylene Carbonate Copolymer

In a 100 ml eggplant flask, 5.82 g (29.4 mmol) methacrylic acid methacrylic lactone, 4.17 g (29.4 mmol) glycidyl methacrylate, Telfon ^TM -coated sterling bar, 19.6 ml dioxane and 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) was added and the mixture was stirred at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Telfon ^™ coated sterling bar, and a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of NMP. The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. Fresh precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was lactone: carbonate = 49: 51. The transmittance | permeability in wavelength 248nm and 193nm of this copolymer is 96% and 65% (1 micrometer in film thickness, on a quartz substrate), respectively, and shows that transparency is excellent. In addition, other analysis results are as follows.

Quantity: 6.79 g (68%)

Weight average molecular weight: 16500 (standard polystyrene equivalent)

Dispersion: 1.75

IR (KRS-5, cm- ¹ ): 1814, 1738, 1260, 1160, 1107.

Example 6

Synthesis of Methacrylic Acid Mealonic Lactone / Methacrylic Acid 2,3-cyclohexanecarbonate Copolymer

In a 100 ml eggplant flask, 5.82 g (29.4 mmol) methacrylic acid methacrylic acid lactone, 5.35 g (29.4 mmol) methacrylic acid 2,3-cyclohexaneoxide, Telfon ^TM -coated sterling bar, 19.6 ml of dioxane and 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) were added and the mixture was stirred at 70 ° C. for 8 hours under a nitrogen atmosphere. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Telfon ^™ coated sterling bar, and a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of NMP. The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was lactone: carbonate = 50: 50. The transmittance | permeability in wavelength 248nm and 193nm of this copolymer is 96% and 65% (film thickness of 1 micrometer, on a quartz substrate), respectively, and shows that transparency is excellent. In addition, other analysis results are as follows.

Quantity: 7.96 g (70%)

Weight average molecular weight: 18100 (standard polystyrene equivalent)

Dispersion: 1.81

IR (KRS-5, cm ^-1 : 1815, 1730, 1260, 1160, 1103.

Example 7

Formation of a resist pattern

The copolymer synthesized in Example 1 was dissolved in propylene glycol methyl ether acetate to obtain a 19% by weight solution. Moreover, 8 weight% of (gamma) -butyrolactone was also contained in this copolymer solution as an auxiliary solvent. To the obtained solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^™ -Membrane filter, followed by chipin coating at 3000 rpm on a silicon substrate subjected to HMDS treatment, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. The resist film was exposed with KrF excimer laser stepper (NA = 0.45), baked at 100 ° C. for 90 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. . At an exposure dose of 16.4 mJ / cm ² , a line-and-space (L / S) pattern of 0.25 μm could be resolved.

Example 8

Formation of a resist pattern

The copolymer synthesized in Example 2 was dissolved in ethyl lactate to obtain a 16 wt% solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethanesulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, followed by chipin coating at 3000 rpm on a silicon substrate subjected to HMDS treatment, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. After exposing this resist film with KrF excimer laser stepper (NA = 0.45), it baked at 120 degreeC for 60 second, developed in 2.38% of tetramethylammonium hydrooxide (TMAH) aqueous solution, and rinse for 60 second in deionized water. .

At an exposure dose of 18.6 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved.

Example 9

Formation of a resist pattern

The copolymer synthesized in Example 3 was dissolved in ethyl lactate to obtain a 16 wt% solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered with a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3000 rpm on a silicon substrate subjected to HMDS treatment, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. After exposing this resist film with KrF excimer laser stepper (NA = 0.45), it baked at 120 degreeC for 60 second, developed in 2.38% of tetramethylammonium hydrooxide (TMAH) aqueous solution, and rinse for 60 second in deionized water. .

At an exposure dose of 16 mJ / cm ² , a 0.30 μm line-and-space (L / S) pattern could be resolved.

Example 10

Formation of a resist pattern

The copolymer synthesized in Example 4 was dissolved in ethyl lactate to obtain a 16 wt% solvent. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solvent was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3000 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. The resist film was exposed to KrF excimer laser stepper (NA = 0.45), baked at 120 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydrooxide (TMAH) solution, and rinsed in deionized water for 60 seconds. .

At an exposure dose of 15 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved.

Example 11

Formation of a resist pattern

The copolymer synthesized in Example 5 was dissolved in ethyl lactate to obtain a 16 wt% solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3000 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. The resist film was exposed with KrF excimer laser stepper (NA = 0.45), baked at 100 ° C. for 60 seconds, developed with a 2.38% aqueous tetramethylammonium hydrooxide (TMAH) solution, and rinsed in deinosized water for 60 seconds. did.

At an exposure dose of 18.2 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved.

Example 12

Formation of a resist pattern

The copolymer synthesized in Example 6 was dissolved in ethyl lactate to obtain a 16 wt% solution. Diphenyliodonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added to the obtained ethyl lactate solution and sufficiently dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, followed by chipin coating at 3000 rpm on a silicon substrate subjected to HMDS treatment, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm is obtained. After exposing this resist film with KrF excimer laser stepper (NA = 0.45), it baked at 100 degreeC for 90 second, developed in 2.38% of tetramethylammonium hydrooxide (TMAH) aqueous solution, and rinse for 60 second in deionized water. .

At an exposure dose of 16.2 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved.

Example 13

Formation of a resist pattern

The copolymer synthesized in Example 2 was dissolved in ethyl lactate to obtain an 18% by weight solution. To the obtained ethyl lactate solution, diphenyl iodonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3500 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 100 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. did.

At an exposure dose of ⁶ mJ / cm ² , a 0.18 μm line-and-space (L / S) pattern could be resolved.

Example 14

Formation of a resist pattern

The copolymer synthesized in Example 3 was dissolved in ethyl lactate to obtain a 16 wt% solution. To the obtained ethyl lactate solution, diphenyliodonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3500 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 120 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. did. At an exposure dose of ⁷ mJ / cm ² , a 0.20 μm line-and-space (L / S) pattern could be resolved.

Example 15

Formation of a resist pattern

The copolymer synthesized in Example 4 was dissolved in ethyl lactate to obtain an 18% by weight solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3500 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 100 ° C. for 90 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. did. At an exposure dose of ⁸ mJ / cm ² , a line-and-space (L / S) pattern of 0.18 μm could be resolved.

Example 16

Formation of a resist pattern

The copolymer synthesized in Example 5 was dissolved in ethyl lactate to obtain an 18% by weight solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^TM membrane filter, spin-coated at 3500 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 100 ° C. for 90 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. did. At an exposure dose of ⁷ mJ / cm ² , a line-and-space (L / S) pattern of 0.18 μm could be resolved.

Example 17

Formation of a resist pattern

The copolymer synthesized in Example 6 was dissolved in ethyl lactate to obtain a 16 wt% solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Telfon ^™ membrane filter, spin-coated at 3500 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 120 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. did. At an exposure dose of ⁷ mJ / cm ² , a line-and-space (L / S) pattern of 0.17 μm could be resolved.

Example 18

Evaluation of Dry Etch Resistance

Using the copolymer prepared in Examples 1 to 6, the method described in Example 7 was repeated. Next, in order to evaluate the dry etching resistance of the obtained resist pattern, the silicon substrate was housed in a parallel plate RIE apparatus, Pμ = 200 W, pressure -0.02 Torr, carbon tetrafluoride (CF ₄ ) gas = 100 sccm, sputtering time = CF ₄ sputtering etching was performed on 5 minutes of conditions. In addition, similar evaluation was also performed about the Nagasen positive-type resist NPR-820 (made by Nagasen Industrial Co., Ltd.) and polymethyl methacrylate (PMAA) which are commercially available novolak resists. The results shown in Table 1 below were obtained.

As can be understood from the above results, the etching resistance of the resist composition according to the present invention is about the same as that of NPR-820, and is significantly superior to PMMA as long as it is a resin structure containing a phenol ring or an alicyclic group.

Example 19

Synthesis of 2-methyl-2-bicyclo [2,2,2] octane / methacrylate propylene carbonate copolymer

In a 100 ml eggplant flask, 6.12 g (29.4 mmol) methacrylic acid 2-methyl-2-bicyclo [2,2,2] octane, 4.17 g (29.4 mmol) glycidyl methacrylate, Teflon ^™ A coated sterling bar, 19.6 ml of dioxane and 1.45 g (8.8 mmol) of azobisisobutyronitrile (AIBN) were added and stirred at 70 ° C. under a nitrogen atmosphere for 8 hours. The reaction solution was diluted with tetrahydrofuran (THF) and then added dropwise to 1.5 liters of methanol containing a small amount of hydroquinone. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF again, and the precipitation-drying operation was repeated twice in the same manner as described above. White resin powder was obtained.

Next, the obtained white powder was placed in a 100 ml three-necked flask, followed by a Teflon ^™ coated sterling bar, and a dim rod condenser and a carbon dioxide inlet tube were attached, and then dissolved in 100 ml of NMP. The contents of the flask were stirred at 100 ° C for 3 hours while introducing carbon dioxide by vaporizing dry ice. The reaction mixture was added dropwise to 1.5 liters of methanol. The resulting precipitate was filtered with a glass filter and dried at 0.1 mm Hg and 45 ° C. for 16 hours. The obtained white powder was dissolved in THF, and the same precipitation-drying operation as described above was repeated twice. White resin powder was obtained. The composition ratio of this white powder was examined by ¹ H NMR, and it was found that the copolymerization ratio was bicyclooctane: carbonate = 52: 48. The transmittance | permeability in wavelength 248nm and 193nm of this copolymer is 96% and 64% (film thickness of 1 micrometer, on a quartz substrate), respectively, and shows that transparency is excellent. In addition, other analysis results are as follows.

Quantity: 7.3 g (71%)

Weight average molecular weight: 14200 (standard polystyrene equivalent)

Dispersion: 1.88

IR (KRS-5, cm- ¹ ): 1813, 1723, 1259, 1162, 1102.

Example 20

Formation of a resist pattern

The copolymer synthesized in Example 19 was dissolved in propylene glycol methyl ether acetate to obtain a 19 wt% solution. The copolymer solution also contained 10% by weight of γ-butyrolactone as a cosolvent. To the obtained solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Teflon ^™ membrane filter, spin-coated at 3000 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film with a film thickness of 0.7 μm was obtained. The resist film was exposed with KrF excimer laser stepper (NA = 0.45), baked at 100 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and dehydrated for 60 seconds in deionized water. Rinse. At an exposure dose of 18 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved.

Example 21

Formation of a resist pattern

In Example 19, the copolymer was dissolved in ethyl lactate to obtain an 18% by weight solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 5% by weight based on the copolymer was added and completely dissolved. The obtained resist solution was 0.2 μm Teflon^TM After filtration with a membrane filter, spin coating was carried out at 3500 rpm on a silicon substrate subjected to HMDS treatment and prebaked at 130 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. The resist film was exposed with an ArF excimer laser exposure apparatus (NA = 0.55), baked at 100 ° C. for 60 seconds, developed in a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution, and rinsed in deionized water for 60 seconds. Was 7.4mJ / cm²At an exposure dose of, a line-and-space (L / S) pattern of 0.18 μm could be resolved.

Example 22

Evaluation of Dry Etch Resistance

Using the copolymer prepared in Example 19, the method described in Example 20 was repeated. Next, in order to evaluate the dry etching resistance of the obtained resist pattern, the silicon substrate was housed in a parallel plate-type RIE apparatus, Pμ = 200 W, pressure = 0.02 Torr, carbon tetrafluoride (CF ₄ ) gas = 100 sccm, sputtering time = CF ₄ sputtering etch was carried out under conditions that were 5 minutes. In addition, similar evaluation was performed also about the Nagasen positive resist NPR-820 (made by Nagasen Industrial Co., Ltd.) and polymethyl methacrylate (PMMA) which are commercially available novolak registers. The results shown in Table 2 below were obtained.

As can be understood from the above results, the etching resistance of the resist composition according to the present invention is on the same level as NPR-820 and is significantly superior to PMMA.

Example 23

Evaluation of the resolution of the resist film

Methacrylic acid 2-methyl-2-adamantyl / methacrylic acid propylene carbonate copolymer synthesized in Example 3 was dissolved in ethyl lactate to obtain an 18% by weight solution. To the obtained ethyl lactate solution, triphenylsulfonium trifluoromethane sulfonate in an amount of 2% by weight based on the copolymer was added and completely dissolved. The resulting resist solution was filtered through a 0.2 μm Teflon ^™ -Membrane filter, spin-coated at 4000 rpm on a HMDS-treated silicon substrate, and prebaked at 120 ° C. for 60 seconds. A resist film having a film thickness of 0.5 μm was obtained. After exposing this resist film with ArF excimer laser exposure apparatus (NA = 0.55), it bakes at 120 degreeC for 60 second, develops in 2.38% of tetramethylammonium hydroxide (TMAH) aqueous solution, and rinses for 60 second in deionized water. did. At an exposure dose of 16 mJ / cm ² , a 0.25 μm line-and-space (L / S) pattern could be resolved. In addition, the adhesion of the obtained resist pattern to the substrate was strong, and no peeling occurred during rinsing.

Next, for comparison, 2-methyl-2-adamantyl / methyl methacrylate (copolymerization ratio = 51: 49, weight average molecular weight = 18500 in terms of standard polystyrene) and dispersion degree in place of the copolymer. = 1.88) was repeated. When rinsed in deionized water, a resist pattern having a width of 0.35 μm or less was peeled off from the substrate, which was less than resolution. This shows that high resolution is easily obtained by using propylene carbonate for one of the monomer units as in the present invention.

Example 24

Fabrication of MOS Transistors

A gate oxide film was formed on the surface of the silicon substrate, and a poly-silicon film was again formed on the surface of the silicon substrate by CVD to reduce the resistance by heavy n-type impurities such as phosphorus. Thereafter, a WSi film was formed by sputtering. Next, a resist pattern of 0.30 µm L & S was formed on the WSi film as the uppermost layer by the method described in Example 9. Using the obtained resist pattern as a mask, the underlying polysilicon film and the WSi film were anisotropically etched. A gate electrode made of a polysilicon film WSi film was formed.

After formation of the gate electrode, phosphorus was implanted by ion implantation to form an N-diffusion layer having an LDD structure. Next, after the resist film on the gate electrode was peeled off, the oxide film was entirely formed by CVD. In addition, the formed CVD oxide film was anisotropically etched to form sidewalls on the sidewall portions of the gate electrodes made of the polysilicon film and the WSi film. Thereafter, ion implantation was performed using the WSi film and the sidewall as a mask to form an N ⁺ diffusion layer. Subsequently, in order to activate this, the silicon substrate was blood-treated in nitrogen atmosphere, and it heated in oxygen atmosphere after that. A thermal oxide film was formed covering the gate oxide film.

After the entire interlayer insulating film was formed by CVD on the uppermost layer of the substrate, the resist solution was again applied and selectively etched according to the method described in Example 14 to form a fine hole pattern of 0.2 mu m in the wiring forming portion. In this resist process, an ArF excimer laser exposure apparatus (NA = 0.55) was used instead of KrF excimer laser stepper (NA = 0.45). In addition, an interlayer insulating film underlying the resist pattern as a mask was anisotropically etched to form a contact hole. Finally, an aluminum (Al) wiring was filled in this contact hole to complete an N-channel MOS transistor.

In this embodiment, the fabrication has been described with reference to a MOS transistor as an example of a semiconductor device. Moreover, by applying this invention, pattern formation of a mask substrate, a reticle, etc., and manufacture of other apparatus can also be performed advantageously. The present invention can also be advantageously applied to patterning on substrates such as glass substrates used in display devices such as LCDs.

By using the resist composition according to the present invention, it is possible to form a fine positive resist pattern with high sensitivity and without swelling. In particular, in the resist composition, not only the protecting group such as the carboxylic acid or the phenol protecting the phenol can be detached by an acid catalyst reaction, and the cyclic carbonate portion contained in one monomer unit constituting the polymer as the base resin is exposed to the exposed portion. Since the reaction rate with the developer is increased, the dissolution rate of the exposed portion is improved, so that higher sensitivity and higher resolution can be easily obtained as compared with the conventional chemically amplified resist.

In addition, when the polymer as the base resin is a polymer using a relative monomer having a phenol or a polycyclic alicyclic group, a dry etching resistance is high, and in particular, when a structure in which the (meth) acrylate polymer does not contain a conjugated double bond is selected, Since the chromophore having a large extinction coefficient is not included in the deep ultraviolet region, it is possible to cope with extreme light and long exposure light sources such as an ArF excimer laser.

In addition, the resist film formed by using the resist composition of the present invention has extremely good adhesion to the substrate to be treated under the ground, and thus has no disadvantage of peeling off from the substrate in the shape as in the prior art.

Moreover, since the excellent resist composition mentioned above is used for manufacture of the semiconductor device of this invention, the device which has a finer gate electrode and a contact hole than before can be manufactured.

Claims (18)

Monomer units I and (B) cyclic carbonates which are polymers insoluble in their basic aqueous solution and which have carboxylic acids or phenols protected with a protecting group desorbable with an acid selected from the group consisting of (A) ester groups, ether groups, acetal groups and ketal groups A substrate comprising a monomer unit II having an ester group or an ether group containing a moiety, at least in its structure, and made of a polymer which can be made soluble in a basic aqueous solution when the reversion of the monomer unit I is released by the action of an acid. A resist composition developable with a basic aqueous solution, comprising a resin and a photo acid generator capable of generating an acid which may cause desorption of the protecting group of the monomer unit I by absorbing and decomposing the imaging radiation. The resist composition according to claim 1, wherein the monomer unit I having a protected carboxylic acid is a (meth) acrylate-based monomer unit. A resist composition according to claim 1, wherein the resist composition is a vinylphenol-based monomer unit of monomer unit I having a protected phenol. The resist composition according to any one of claims 1 to 3, wherein the ester group which is a protecting group of the monomer unit I is an alicyclic hydrocarbon group. The resist composition according to claim 4, wherein the alicyclic hydrocarbon group has a tertiary alcohol skeleton and is ester-bonded with the tertiary alcohol. The resist composition according to claim 4, wherein the alicyclic hydrocarbon group has a polycyclic alicyclic skeleton. The resist composition according to any one of claims 1 to 3, wherein monomer unit II having an ester group or ether group comprising a cyclic carbonate moiety is a (meth) acrylate-based monomer unit. The resist composition according to any one of claims 1 to 3, wherein the polymer does not have a conjugated double bond in its structure. The resist composition according to any one of claims 1 to 3, wherein the photo acid generator is contained in an amount of 0.1 to 50% by weight based on the total amount of the base resin. The resist composition according to any one of claims 1 to 3, wherein when the coating is applied to a quartz substrate to form a film having a film thickness of 1 m on the substrate, the transmittance at the exposure wavelength at that time is 20% or more. . 4. A compound according to any one of claims 1 to 3, consisting of ethyl lactate, methylamine ketone, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate and mixtures thereof. Resist composition characterized in that the form of a solution dissolved in a solvent selected from the group. The resist composition according to claim 11, further comprising a solvent selected from the group consisting of butyl acetate, γ-butyrolactone, propylene glycol methyl ether, and mixtures thereof as an auxiliary solvent. The following steps: The resist composition according to claim 1 is applied onto a substrate to be treated, and the formed resist film is selectively exposed to imaging radiation capable of inducing decomposition of the photoacid generator of the resist composition, and the resist after exposure. And developing the film with a basic aqueous solution. The method of forming a resist pattern according to claim 13, wherein in the exposure step, a KrF or ArF excimer laser is used as an exposure light source. The following process: The resist composition according to claim 1 is applied onto a substrate to be treated to form a resist film, and the resist film is selectively exposed to imaging radiation capable of inducing decomposition of the photoacid generator of the resist composition. And developing the resist film after exposure to a basic aqueous solution to form a resist pattern, and removing the substrate under processing by etching with the resist pattern as a mask. The method of manufacturing a semiconductor device according to claim 15, wherein the substrate to be processed has an etching target layer applied thereon. The semiconductor device manufacturing method according to claim 15 or 16, wherein in the exposure step, a KrF or ArF excimer laser is used as an exposure light source. The resist composition according to claim 5, wherein the alicyclic hydrocarbon group has a polycyclic alicyclic skeleton.

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